diff --git a/SAS/LSMR/docker/lsmr/Dockerfile b/SAS/LSMR/docker/lsmr/Dockerfile
index fdc248ff33044074b50867ffa4f68a6f15ef4a10..960bcff757da769d6328a8e0a5ff77de8c0aaa97 100644
--- a/SAS/LSMR/docker/lsmr/Dockerfile
+++ b/SAS/LSMR/docker/lsmr/Dockerfile
@@ -13,7 +13,7 @@ RUN apt-get -y install make cmake g++ subversion python3 git
 
 # LOFAR build dependencies
 RUN apt-get -y install liblog4cplus-dev python3-dev libldap2-dev libsasl2-dev
-RUN apt-get -y install python3-pip && pip3 install django djangorestframework django-filter django-auth-ldap coreapi python-ldap-test django-jsonforms django-json-widget "git+git://github.com/nnseva/django-jsoneditor.git" psycopg2-binary markdown ldap3 drf-yasg
+RUN apt-get -y install python3-pip && pip3 install django djangorestframework django-filter django-auth-ldap coreapi python-ldap-test django-jsonforms django-json-widget "git+git://github.com/nnseva/django-jsoneditor.git" psycopg2-binary markdown ldap3 drf-yasg flex
 
 # Install LOFAR packages
 RUN mkdir /src && \